California Governor Arnold Schwarzenegger has denied clemency to former gang leader and convicted murderer Stanley "Tookie" Williams, who is set to be executed Tuesday.

A spokesman for Mr. Schwarzenegger said the governor made his decision Monday. The announcement comes less than one hour after a California appeals court also refused to block Williams' execution. He is scheduled to die by lethal injection just after midnight Pacific coast time (0801 UTC) Tuesday.

He was convicted of the murders of four people in 1979, but has consistently denied committing the murders.

Williams is a co-founder of the infamous Crips street gang. While in prison, he has written a series of books warning young people about the dangers of gangs. His lawyers argue the books are evidence he has turned his life around during his 24 years in prison.